Steam generator



Jan. 14, 1941. 'r a s-n 2,228,981

STEAM GENERATOR Filed 001:. 12, 1938 5 sheets sheet l ZNVENT OR.

7725mm 5 Sfz'Z/man ATTORNEY.

Jan. 14, 1941. sTlLLMAN 2,228,981

swam GENERATOR Filed Oct. 12, 1938 5 Sheets-Sheet 2 Fi .1 F

IN VENTOR.

Thomas B. Szfz'Z/marz ATTORNEY.

an, 14,, 1941. T. B. STILLMAN STEAM GENERATOR Filed 001;. 12., 19:58

5 Sheets-Sheet 3 INVENTOR.

T'roRNEY.

Jam. 14, 1941.

T. B. STILLMAN $228,981

STEAM GENERATOR Filed Oct. 12,1938 5 Sheets-Sheet 4 UUUU w F n HINVENTOR.

Thomas .5. Sizf/man ATTORNEY.

Jan. 1941; T. B. STILLMAN 2,228,981

STEAM GENERATOR Filed Oct. 12, 193B 5 Sheets-Sheet 5 onooo manna cacaoINVENTOR.

Thomds B. SEN/man STEAM GENERATOR Thomas B. Stillman, South Orange, N.1., assignor to The Babcock at Wilcox Company, Newark, N. 1., acorporation of New Jersey Application October 12, 1938, Serial No.234,526 1 '15 Claims.

The present invehtion relates to the construction and arrangementofinternal baflle systems for a steam and water drum of a water tube steamboiler, and, more particularly, a steam boiler hav- 5 ing a multiplicityof steam generating tubes discharging directly into the water space ofthe drum.

With the small diameter high capacity steam and water drums used inthree drum express type 1D marine boilers, for example-,it has beenfound extremely difficult to carry a water level above the center lineof the drum without danger of substantial moisture carryover in theoutgoing steam. This is due to a tendency for the steam to and waterdischarged from the tubes to flow up through the water locally andviolently disturb the water surface. When such boilers are employed, thefeed water supply to the boiler is ordinarily manually controlled by awater tender.

20 Rapid and substantial fluctuations in the drum water level whichoccur when turbulent conditlons are present in the water, render thewater tending operations difficult.

In such boilers, various arrangements of sub- 25 merged bafiles havebeen suggested for reducing turbulence of the water in the steam andwater drum by attempting to effect uniform liberation of the steam overthe area of the water surface. One such bafile arrangement which has metwith 30 fair success is shown in the Donald Patent 1,884,614 as asubmerged V-shaped perforated baflle in the path of discharge of thegenerating tubes having the highest rate of steam generation. With highwater levels and increasing steaming 35 capacities, the Donaldarrangement has been found to be inadequate to maintain a substantiallydry steam discharge and steady water level conditions.

The main object of my invention is the provi- 40 sion of an improvedconstruction and arrangement of a submerged bafile system for a steamand water drum of a steam boiler of the character described, theoperation of which is characterized by the maintenance of asubstantially 45 dry steam discharge and steady water levels in the drumunder high capacity operation, even with high water levels in the drum.

The various features of novelty which characterize my invention arepointed out with particu- 50 larity in the claims annexed to and forminga part of this specification. For a, better understanding of theinvention, its operating advantages and specific objects attained by itsuse, reference should be had to the accompanying 55 drawings anddescriptive matter in which I have I Cl. 122-491) illustrated anddescribed preferred embodiments of my invention.

f the drawings: Fig. 1 is a sectional elevation of a three drum expresstype marine boiler having a steam and water drum baflle systemconstructed in accordance with my invention;

Fig. 2 is an enlarged view of the steam and water drum of Fig. 1;

Fig. 3 is an enlarged view of the feed pipe shown in Fig. 2;

Fig. 4 is an enlarged view of the dry pipe shown in Fig. 2;

Fig. 5 is a. horizontal section taken on the line 5-4 of Fig. 2;

Fig. 6 is a vertical section taken on the line B-6 of Fig. 2;

Fig. 7 is a plan view of the V-shaped baffle taken on the line l--'l ofFig. 2;

Fig. 8 is a view similar to Fig. 2 illustrating a modified construction;and

Figs. 9 and 10 are full size sectional views taken on the lines 99 andIll-IO respectively of Fig. 8.

While my invention is applicable to various types of steam boilershaving a submerged connection of th steam generating tubes into a steamand water drum, it is particularly designed for and especially useful inthree drum express type marine boilers, such as shown in Fig. 1. Thesteam boiler illustrated has a horizontally arranged steam and waterdrum ill connected to a pair of laterally offset parallel lower waterdrums H and I2 by oppositely inclined banks of water tubes l3 and IIrespectively. The inverted V- shaped chamber therebetween is divided bya vertical partition 15 into separate furnaces l6 and ll. The partitionincludes a row of water tubes l8 connected to the drums Ill and H. Thetube bank I3 is divided into a pair of spaced tube groups and the spacetherebetween utilized for 4 the installation of a steam superheater 19.Each furnace is heated by a separate group of fuel burners,diagrammatically indicated at 2B, in one of its end walls and theheating gases after traversing the corresponding tube bank pass acrossan extended surface economizer 21 to the stack. With this construction,only the furnace I1 is used in starting-up and the furnace l8 operatedwhen there is an adequate flow of steam through the superheater. Controlof the firing or combustion in the furnace I 6 is used to regulatesuperheat temperatures, and that in furnace H to regulate the generationof steam.

As shown in Figs. 2 and 3, feed water is supplied to the steam and waterdrum through a submerged feed pipe 25 entering through one end of thedrum and capped at its other end. Holes 26 along the upper side of thefeed pipe provide a distribution of the feed water along the length ofthe drum. A dry pipe 21 extends along adjacent the top of the drum withholes 28 in its upper side for the passage of steam. The dry pipe isconnected to a central steam outlet 29 and a safety valve connection 30.

In the boiler described, the designed water level in the steam and waterdrum is at the horizontal center line of the drum. As shown in Figs. 1and 2, all of the tubes in the tube banks l3 and [4 enter the drum belowthis level.

With furnaces l6 and H in operation, most of the steam will be generatedin the portions of the tube banks nearest the furnaces and the tubes inthe outer portions of the tube banks will serve as downcomers,supplemented by groups of downcomers 3| at the ends of the tube banks.The submerged discharge of a multiplicity of high velocity streams ofsteam and water upward through the water along the longitudinal centralpart of the drum tends to effect a highly turbulent condition in thewater space of the drum with a high exit velocity of the steam leavingthe water space mainly above the tubes nearest the furnace. Suchconditions contribute to entrainment of water by the steam leaving thewater space and the production of wet steam with a relatively high solidcontent. With the drum baflle system of I my invention, a substantiallyuniform liberation of steam at a reduced water exit velocity across theentire water surface is effected.

My improved drum bafile system is divided as shown in Fig. 1, into threeparts, a lower V-shamd bafiie Ml, a pair of wing baflles 5t, and ahorizontal center baiile 60. The V-shaped bafie 60 is formed by twooppositely inclined perforated steel plates ll having upturned flangedinner edges 52 connected together along the vertical center line of thedrum. The baffle plates E-l are supported at an acute angle to thehorizontal, approximately 20, superjacent the feed pipe 25. TheV-bafiile is supported by correspondingly bent plates carried by thefeed pipe, which in turn is sup ported at longitudinally spaced pointsby recessed bars 46 suspended from angle members d5 lay hanger bolts 66.The angle members 35 extend across the drum at about its water line andare carried by bent plates il welded to the drum wall. The hanger bolts46 are surrounded by spacer sleeves 68 and extend downwardly through thebaflie plates M to hold the feed pipe and thereby the V-baiiie fixed inposition with the apex of the baiile approximately half way down belowthe designed water level.

Each of the wing bafiies 58 is formed by per= forated steel plates 5iconnected to one side wall of the drum at the designed water level andsloping downwardly to a point below the water level and in approximatevertical alignment with the corresponding outer edge of the V-bafile.The baflie plates 55 have flanged edge portions to permit theirconnection to one another and to the supporting angle members at. Thewing bames terminate short of the full length of the V-bafile and spacestherebeneath are closed at their ends by perforated vertical angleplates 52. The plates 52 partly surround the upper ends of thedowncomers 3| and function to separate steam from the water in the drumflowing to the downcomers 3|.

The horizontal center bafiie 60 is formed by perforated flat steel platesections 6| having upturned flanged edge portions connected to adjacentplates and to the angle members 45 and inner edge portions of the wingbaflles 50. The center baiile is arranged below the designed waterlevel, slightly below the inner edges of the wing battles, and extendsslightly beyond the ends of the V-baflle. The hanger bolts 46 andsleeves 48 extend through the corresponding plate sections 6|. The sidesof the space below the center baille beyond the ends of the wing bamesare closed by perforated bent sections of the end plates 52.

The perforations in the baille plates 4|, BI, 52 and GI illustrated areformed by holes V in diameter staggered throughout the plate area andtotaling about 25% of the plate area.

Surface blow-off operations can be effected through a horizontallyarranged perforated blowoff pipe 10 extending longitudinally of the drumjust above the center baflle 60. The pipe III is supported from theangle members 45 by U- bolts l|.-

The drum battle system described has been found to be highly effectivefor its intended purposes. In one test installation having 4360 sq. ft.of boiler heating surface and a drum pressure of 600 lbs. per sq. in.,it was found that when generating 154,596 lbs. of steam per hr. (143%rated capacity) corresponding to 54.5 cu. ft. of steam per minute persq. ft. of drum water surface, the moisture in the outgoing steam wasless than of 1%. Under full power conditions it was found possible tocarry' a water level within 1 from the top of the gauge glass with lessthan 0.6 of 1% moisture in the delivered steam.

In operation, the high velocity streams of steam and water entering thedrum impinge upon the feed pipe 25 and V-baiiie to which causes them tobe dispersed throughout the width of the drum. Some of the streams aredeflected towards the sides of the drum by the inclined arrangement ofthe V-baffle plates and these streams are obstructed and broken up bythe wing baffles 58 before leaving the water space. in view of the lowlocation of the V-bafile and the high velocity steam discharge, some ofthe streams will pass through the V-baffie perforations at a highvelocity and these streams are later obstructed dispersed by the centerbafiie. The various submerged batfles thus cooperate to provide asubstantially uniform flow of steam from all of the liberating surfaceof the drum above the con nected tubes in spite of its relativelylocalized admission to the bottom of the drum. At the same time thelarger steam bubbles are broken up and the water separated from thesteam.

In Figs. 8-10 is illustrated a modified bafile construction alsoparticularly adapted for use in steam boilers of the type described. Inthe modi fled construction, the amount of perforated bafile area in thedrum I6 is substantially increased and arranged as hereinafterdescribed. The perforated bafiie area of the lower V-shaped baiiie 4B isincreased by the addition of, perforated plates 80 and below and aboverespectively each section thereof. While the plates M are constructedwith diameter perforations totaling about 25% of the plate area, it hasbeen found desirable to make the plates 39 and ill with perforations indiameter and totaling about 20% of the plate area. their extent andarranged in contact with the underside of the plates 4| to reduce theeffective flow area through the plates 45. The plates 8! have their edgeportions similarly bent to form a shallow dish-shaped structure andarranged with The plates 86 are made fiat throughout their bent edgeportions in contact with the corresponding plate lH. The perforated bodyof each plate 8| is held in the spaced relation with the plate 4|described and the plates 40,280 and 8| 5 held assembled by any suitablemeans, such as the bolts 82. Perforated plates 90 similar inconstruction to the plates 8| are arranged at opposite sides of eachwing baiile plate 5| and each center bafiie plate 6|. The modifiedbaiile construction described has been found to result in a lowermoisture content of the steam delivered under similar boiler load andwater level conditions than the baffle construction shown in Figs. 17,even with a high solid concentration in the boiler water.

While in accordance with the provisions of the statutes 1 haveillustrated and described herein the best forms of the invention nowknown to me, those skilled in the art will understand that changes maybe made in the form of the apparatus disclosed without. departing fromthe spirit of the invention covered by my claims, and that certainfeatures of my invention may sometimes be used to advantage without acorresponding use of other features.

This application is a continuation in part of my prior applicationSerial No. 169,080, filed Oct. 15, 1937. r

I claim:

i. In a vapor generator, a liquid and vapor 3a drum having vaporgenerating tubes connected to the lower part thereof, a submergedV-shaped perforated baiiie extending in an upright position across thepath of discharge from said vapor generating tubes and having its sideedges spaced from the corresponding sides of said drum, and ahorizontally arranged baille structure extending across saiddruin abovesaid V-baifle and comprising a plurality of vertically spaced perforatebailles, the total flow area through the uppermost baiiie being 4a lessthan the total flow area through the sub- ;iacent battle.

2. In a vapor generator, a horizontally arranged liquid and vapor drumhaving vapor generating tubes connected to the lower part thereof at op-4d posite sides of the vertical axial plane of said drum,

a submerged V-shaped perforated plate bailie extending in an uprightposition across the path of discharge from said vapor generating tubesand having its side edges spaced from the correspondliil ing sides ofsaid drum, and a horizontally arranged baffle structure extending acrosssaid drum above said V-baflie andcomprising a plurality of norrnallysubmerged vertically spaced perforated plates, the total flow areathrough the uppermost 5% plate being less than the total flow areathrough the subjacent plate.

3. In a steam generator, a horizontally arranged steam and water drumhaving steam generating tubes connected to the lower part thereof, asub- Bll merged v shaped perforated baiiie extending in an uprightposition across the path of discharge from said steam generating tubesand having its side edges spaced from the corresponding sides of saiddrum, a pair of wing baffles above and extending 65 across the spacesbetween said V-bafile and drum wall, and a horizontally arranged baflieextending across said drum above said V-baflle.

l. In a steam generator, a horizontally arranged steam and water drumhaving steam generating tubes connected to the lower part thereof, asubmerged V-shaped perforated baffle extending in an upright positionacross the path of discharge from said steam generating tubes and havingits side edges spaced from the corresponding sides of said 7 drum, apair of submerged perforated wing baiiles above and extending'across thespaces between said V-baflle and drum wall, and a horizontally arrangedsubmerged perforated ballie extending across said drum above saidV-baille and between said wing baflles. 5 5. In a steam generator, ahorizontally arranged steam and water drum having steam generating tubesconnected to the lower part thereof, a submerged V-shaped perforatedhaiile extending in an upright positi'on across the path of discharge 10from said steam generating tubes and having its side edges spaced fromthe corresponding sides of said drum, a pair of submerged perforatedwing bailles above and extending across the spaces between said V-baffleand drum wall, perforated end 15 plates closing said spaces adjacent theends of said said wing baffles. 20 I 6. In a steam generator, ahorizontally arranged steam and water drum having steam generating tubesconnected to the lower part thereof, a submerged shallow V-shapedperforated baiile extending in an upright position across the path of 25discharge from said steam generating tubes and having its side edgesspaced from the corresponding sides of said drum, a pair of oppositelyinclined submerged perforated wing baffies above and ex-- tending acrossthe spaces between said v-baflle and drum wall, and a horizontallyarranged submerged perforated sectional baiiie extending across saiddrum above said V-baflle and between said wing baflies. I

'7. In a steam generator, a horizontally arranged steam and water drumhaving steam generating tubes connected to the lower part thereof, asubmerged V-shaped perforated baflle extending across the path ofdischarge from said steam generating tubes and having its side edgesspaced from the corresponding sides of said drum, a feed pipe extendinglongitudinally of said drum below said V-baffle, and means forsupporting said V-baffle from said feed pipe.

8. In a steam generator, a horizontally arranged 4,5 steam and waterdrum having steam generating tubes connected to the lower part thereof,a submerged V-shaped perforated baflie extending across the path ofdischarge from said steam generating tubes and having its side edgesspaced 5d from the corresponding sides of said drum, a feed pipeextending longitudinally of said drum below said V-baille, means forsupporting said V-baflle from said feed pipe, supporting membersextending across said drum above said V-baflle, and means for supportingsaid feed pipe from said supporting members.

9. In a steam generator, a horizontally arranged steam and water drumhaving steam generating tubes connected to the lower part thereof atopposite sides of the vertical axial plane of said drum, a submergedV-shaped perforated baiile extending across the path of discharge fromsaid steam generating tubes and having its side edges spaced from thecorresponding sides of said drum, .a feed pipe extending longitudinallyof said drum below said V-bafile, means for supporting said V-baiiiefrom said feed pipe, and means for supporting said feed pipe includingsupporting members extending across said drum above said V-baffie,cross-bars receiving said feed pipe, and hanger bolts extending fromsaid supporting members through said V-baflle to said cross-bars.

10. In a vapor generator having a liquid'and vapor drum and vaporgenerating tubes connected to the lower part thereof, a submergedv-shaped baiile extending in an upright position across the path ofdischarge from said vapor generating tubes and having its side edgesspaced from the corresponding sides of said drum, and a horizontallyarranged submerged bailie extending across said drum above saidV-baille, each of said bailles comprising a plurality of superposedperforated plates of different total flow areas.

11. In a vapor generator having a horizontally arranged liquid and vapordrum and vapor generating tubes connected to the lower part thereof atopposite sides of the vertical axial plane of said drum, a submergedV-shaped baffle extending in an upright position across the path ofdischarge from said vapor generating tubes and having its side edgesspaced from the corresponding sides of said drum, and a horizontallyarranged submerged baiile extending entirely across said drum above saidV-bailie, each of said bames comprising a plurality of superposedperforated plates with the perforations in adjacent plates ofsubstantially, different size.

12. In a steam generator having a horizontally arranged steam and waterdrum and steam generating tubes connected to the lower part thereof, asubmerged V-shaped baille extending in an upright position across thepath of discharge from said steam generating tubes and having its sideedges spaced from the corresponding sides of said drum, a pair ofsubmerged wing bailles above and extending across the spaces betweensaid V-baille and drum wall, a horizontally arranged submerged centralbaflle extending across said drum above said V-baflle and between andsupported from said wing baflles, and each of said bailles comprising aplurality of superposed vertically spaced perforated plates with theperforations in adjacent plates of substantially different size andsubstantially the same total flow area.

13. In a steam generator having a horizontally arranged steam and waterdrum and steam generating tubes connected to the lower part thereof,asubmerged V-shaped baiile extending in an upright position across thepath of discharge from said steam generating tubes and having its sideedges spaced from the corresponding sides of said drum, and a pair ofsubmerged wing bailles above and extending across the spaces betweensaid V-baflle and drum wall, each of said wing bailles comprising aplurality of superposed vertically spaced perforated plates.

14. In a steam generator having a horizontally arranged steam and waterdrum and steam generating tubes connected to the lower part thereof, asubmerged V+shaped baflle extending man upright position across the pathof discharge from said steam generating tubes and having its side edgesspaced from the corresponding sides of said drum, said bailie comprisinga plurality of superposed perforated plates with the perforations inadjacent plates of substantially different size.

15. In a steam generator having a horizontally arranged steam and waterdrum and steam generating tubes connected to the lower part thereof, asubmerged shallow V-shaped perforated baflle extending in an uprightposition across the path of discharge from said steam generating tubesand having its side edges spaced from the corresponding sides of saiddrum, said baiile comprising an intermediate perforated plate and a pairof perforated baille members at the upper and lower sides of said plate,said upper baiiie member being arranged in spaced relation and saidlower baflle member in contact with said intermediate plate.

THOMAS B. STIILMAN.

